Friday, June 10, 2011

I just heard about your recognition of Global Wind (Power) Day: June 15. This was on the same day that I was prompted to compare Vermont wind energy's potential effect on greenhouse gas emissions with that of the roughly 150,000 cows in Vermont.

Granted that the global wind industry is lucrative for NRG Systems and Northern Power Systems among others, but considering the huge impact of erecting wind turbines on Vermont's ridgelines, is the potential environmental benefit worth it?

The Public Service Board has approved 145 MW of new wind projects in Vermont (in Sheffield, Milton, Readsboro, and Lowell). At a capacity factor of 25%, they would be expected to produce (and thereby theoretically displace) 317,550 MWh per year, or less than 5% of Vermont's total electricity production (or just over 5% of the state's total demand).

That in itself is a rather low number, considering the substantial impacts of these facilities. The potential environmental benefit, however, is even smaller when it is remembered that Vermont is ranked by the U.S. Energy Information Administration as 51st in CO₂ emissions from electricity generation.

The EIA estimates Vermont's CO₂ emissions from electricity generation to be about 10 million kg annually, or 1,430 g/MWh.

Now for the cows: An average cow is estimated to emit about 275 kg of methane gas annually, and methane has 25 times the greenhouse gas effect of CO₂. Along with its exhalations of CO₂, the CO₂-equivalent emissions from one cow is therefore about 8,000 kg annually.

Conclusion: 145 MW of wind in Vermont will theoretically save just over 450,000 kg of CO₂ emissions, which is the equivalent of removing 56 cows out of the state (even fewer if their manure is factored in).

Nobody can pretend that the severe alteration of ridgeline ecosystems, habitat destruction and fragmentation, direct harm to wildlife, and aesthetic vandalism that are a necessary part of these projects are truly balanced by such inconsequential benefits.